Food Processing-Jaw-dropping Science Behind Preservatives and Additives

Food Processing-Jaw-dropping Science Behind Preservatives and Additives

Vegetables and fruits are most likely to be processed and preserved to be sold as different food products in supermarkets. This article primarily focuses on the jaw-dropping science involved in the processing of vegetables.
Although many vegetables are eaten raw without processing, an extensive range of food products is obtained from all kinds of vegetables.
Below is the list of some commonly used vegetable-based food products obtained from processing:
1. Frozen vegetables
2. Canned Vegetables
3. Vegetable juice
4. Concentrated vegetable juice
5. Pickles and vegetable powders
6. Dried pulps of vegetables
All these vegetable products are used for food preparation and can be stored for prolonged use.

Different Vegetable-Based Food Products

Two main approaches can be stated to list vegetable-based food products.

Processed vegetable products

These are the products that are manufactured after the use of industrial techniques to come up with a variety of vegetable-based products to be used directly or after preparing adequately.

Food products made from vegetables after cooking

Processed and fresh vegetable-based products can be handled using diverse cooking techniques to prepare meals and cooked vegetable-based food.


Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food’s texture and flavour. The resulting food is called a pickle.

Method of pickling


There are three general methods for vinegar-brine pickling.
1. Quick-pickling
2. Salt-brine pickling
3. Chemical pickling
4. Refrigerator pickles

Quick pickling

They are simply vegetables that are pickled in a vinegar, water, and salt (sometimes sugar, too) solution and stored in the refrigerator. Quick pickles don’t develop the deep flavor that fermented pickles do, but they only require a few days in the brine before they can be enjoyed.

Salt brine pickling

These pickles are fermented in a salt brine, not in vinegar, and get their delicious tanginess from light fermentation rather than vinegar. Full of healthy, gut-healing, immunity-boosting probiotics, these little guys are perfect as a low-calorie snack, sliced and added to sandwiches, or served as a tasty side.

Chemical pickling

In chemical pickling, the fruits or vegetables to be pickled are placed in a sterilized jar along with brine, vinegar, or both, as well as spices, and are then allowed to mature until the desired taste is obtained.

Refrigerator pickles

Refrigerator pickles” are unfermented pickles made by marinating fruit or vegetables in a seasoned vinegar solution. They must be stored under refrigeration or undergo canning to achieve long-term storage.


It is one of the most used processes for the preservation or storage of food. It is based on heat removal of the food to be conserved by keeping the temperature sufficiently low to reduce the destructive action of the microorganisms, oxygen, and enzymes on the product.

Types of Freezing:-

Freezing of food can be done by different processes, like;
1. Blast freezers
2. Tunnel freezers or IQF
3. Cryogenic freezing
4. Fluidized-bed freezers
5. Home Freezing

Home Freezing:-

It is an excellent way to preserve Fresh vegetables at home. Freezing at home does not sterilize food; the extreme cold retards the growth of microorganisms and slows down changes that affect the quality or cause spoilage in food.

Blast freezing:-

Blast freezing is pushing cold air at high velocity across a food product to freeze the product as quickly as possible. High-quality food products can be moved into high-price markets, but low-quality products are left to low-quality needs.

Tunnel freezing or IQF:

They are specialized freezers capable of freezing large quantities of vegetable products in short periods while ensuring that the products are frozen without causing any clumps from developing or having the product stick together, thereby compromising quality.

Fluidized-bed freezers:-

Fluidized-bed freezers freeze particulate foods such as peas, cut corn, diced carrots, etc. The foods are placed on the mesh conveyor belt and moved through a freezing zone in which cold air is directed upward through the mesh belt, and the food particulates begin to tumble and float. This tumbling exposes all sides of the vegetable product to cold air and minimizes the resistance of heat transfer at the surface of the food.

Cryogenic Freezing:-

Cryogenic freezing is used to freeze food at a fast rate. The food is moved through a liquid nitrogen spray or immersed in liquid nitrogen. The liquid nitrogen boils around the food at a temperature of -196 °C (-321 °F) and extracts a large amount of heat. And it also stores the human remains, with the speculative hope that resurrection may be possible in the future.

Examples of Frozen Vegetables:-

Following are some commonly found frozen vegetables in the market:
• Broccoli
• Peas
• Corn
• Yam
• Cauliflower, etc.



It is the method of preserving food with dry edible salt. This method is similar to advanced refrigeration. In this method, food is kept by removing excess moisture content in food to protect food from spoilage and microbial growth. Salt ( Sodium chloride ) has been used for preserving vegetables for centuries.



Slice the vegetables.
Sprinkle a little salt on both sides and pat it with your hand.
Place it in a bowl for about 15-30 minutes.
After 15-30 minutes, rinse them quickly to remove excess salt and dry it.
Salted vegetables are used in baking, coating, or breading so the food will not be soggy and retain its physical appearance for hours. Like in salads, for dressings, those vegetables are required that sustain their shape and will not be turned in yellow or brown color.


Canning Of Vegetables

Canning is a process used for the preservation of food, and it increases its shelf life for up to months. In this process, vegetables are peeled, sliced, and packed in cans. Canning preserves food because it ceases the entry of bacteria, fungi, and other microorganisms that cause food spoilage. The vegetable cans are heated at a high temperature, and a vacuum is created inside the can when it is cooled down.Methods Of Canning:

There are two methods of canning that are widely used. One is pressure or steam canning, and another one is water-bath Canning.

Pressure Canning:

Pressure canning is when low acid-containing vegetables such as acidified tomatoes, pickles, and sauerkraut are sealed in cans. Then cans are subjected to high heat that builds pressure in them.

Water-bath Canning:

The vegetables are first peeled off and sliced into fine pieces. Then they are thoroughly washed but not subjected to heat. Afterward, they are added to a can, and the lid is tightly closed. In the last step, the can is placed in boiling water and thoroughly sterilized. Properly canned vegetables can be stored for up to 18 months.


Dehydrated vegetables are a typical example of vegetable-based processed food. They serve as value-adding products to the national and international markets. The drying techniques require energy consumption but greatly benefit the food industry.
There are many methods of dehydrating vegetables, but the following are the most commonly used methods:
1. Sun Drying/ solar dehydration
2. Osmotic Dehydration
3. Freeze drying
4. Tray drying


Selection of Vegetables:

In the first step, fresh Vegetables are separated to be processed further. All the vegetables which do not meet the quality standards are discarded, and fresh vegetables are moved on to the next steps.
Cleaning/Washing and Disinfection:
The second step is to clean and wash the vegetables thoroughly and disinfect them to eliminate any foreign insects or insecticides.

Blanching Vegetables:
It is the third step of dehydration in which the vegetables are scalded in boiling water for a short interval of time

Cooling in trays:
The vegetables are then cooled in trays.

An important step is sulfating, in which the vegetables are exposed to sulfur fumes which prevent the mold growth
Sun Drying and Packing:
After this, the vegetables are sun-dried ( using solar energy) and then packaged for storage.


Concluding all the facts stated above, it is evident that vegetables are essential value-adding factors to the global food industry. Through various processing techniques, vegetables are converted to food products available in markets. The wide diversity of vegetable-based processed food products is essential in rendering feasibility in preparing different food items.
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